An electronic device, for example, a liquid crystal display or a CCD/CMOS image sensor, undergoes exposure to a solvent or a chemical liquid such as an acid or alkali solution, or exposure to a high temperature through sputtering, dry etching, solder reflow and the like in a manufacturing process thereof. In order to prevent degradation of or damage to an element by such treatments, a cured film resistant to such treatments, as a protective layer, is formed on the element. For such a protective film, chemical resistance, high transparency, heat resistance, moisture resistance, and the like. are required. To manufacture an electronic device having high reliability, the cured film also needs long-term heat resistance and moisture resistance.
When the cured film is formed on an uneven surface such as a color filter, in terms of ensuring process margin in a subsequent process or the uniformity of device properties, a cured film with high planarization property is required. In addition, a microlens is also manufactured from such the cured film.
A known method for manufacturing a microlens for a CCD/CMOS image sensor is an etch back method (Patent Documents 1 and 2). In other words, a resist pattern is formed on a resin layer for a microlens, which is formed on a color filter, and then reflowed by thermal treatment, thereby forming a lens pattern. The underlying resin layer for a microlens undergoes etch-back using the lens pattern formed by reflowing the resist pattern as an etching mask, and the shape of the lens pattern is transferred to the resin layer for a microlens, thereby manufacturing a microlens.
For example, in Patent Document 3 to Patent Document 5, resin compositions used for forming a microlens are disclosed. However, all compositions are photosensitive (radiation-sensitive) resin compositions, and the compositions may not be suitable materials for forming a microlens by performing the above-mentioned etch-back method.
In Patent Document 6, a non-photosensitive resin composition used for forming a microlens is disclosed. However, the moisture resistance of a film formed from the non-photosensitive resin composition is not known.